Today I noticed that
ViGEmBusUpdater.exe ran on my system. Because when it did, I got a certificate warning as it attempted to query the update URL.
I looked into it real quick, and saw that the TLS certificate for updates.vigem.org expired essentially today.
The other ViGEm website certificates seem to be fine; so perhaps you just need to double-check your Let's Encrypt / Certbot settings for the
updates. subdomain in particular and make sure that it gets renewed properly. Because it looks like the auto-renewal process just isn't happening for it right now.
(Or maybe just go for a wildcard certificate for the entire domain? It's been a little while since I last messed around with Let's Encrypt, so I forget how easy or difficult those are to do. I suppose the feasibility of integrating that may depend on the specifics of your overall setup too...)